Yes we loved the lagoon and loved Iceland.
We are both seniors and asked for the discount.
After we were inside for a bit we realized that we had paid $120 US for 2 of to get in.
We went back to the desk and they agreed to discuss the situation when we exited.
Yes, they had "overcharged" us and gave us about $28, back, this was after quite sometime and the original person who had checked us in had vanished.
If you can take your own towels and your own robes from your Hotel it would be worth it as the blue lagoon charges for everything. If you are a senior make sure you get the discount double check the charges at the desk, and count your change It is too bad that such a nice place does not appear to be honest when it comes to discounts. I did write to them twice asking them to clarify the charges to which I never received a reply.